Write the IUPAC names of each of the following:
1. `H-overset(H)overset(|)C=overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H`
2. `H-underset(H)underset(|)overset(H)overset(|)C-C-=C-underset(H)underset(|)overset(H)overset(|)C-H`
3. `H-underset(H)underset(|)overset(H)overset(|)C-overset(H)overset(|)C=O`

Explanation

To write the IUPAC names for the given compounds, we will follow the systematic approach of identifying the longest carbon chain, determining the functional groups, and applying the appropriate nomenclature rules.

### Step-by-Step Solution:

1. **First Compound: H-CH=CH-CH3**
- Identify the longest carbon chain: The longest chain has 3 carbon atoms (C1, C2, C3).
- Identify the type of bond: There is a double bond between C1 and C2.
- Number the carbon chain: Start numbering from the end closest to the double bond to give the double bond the lowest number. Thus, C1 (double bond) - C2 - C3.
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